Fix ia64-linux miscompilation or tcl/generic/tclCompExpr.c

Fix ia64-linux miscompilation or tcl/generic/tclCompExpr.c
	* loop.c (check_final_value): Check for biv use before checking for
	giv use.  Check for both biv and giv uses.  Always set last_giv_use
	if there is a giv use.

From-SVN: r36104

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 166df7a..8e0b387 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2000-09-01  Jim Wilson  <wilson@cygnus.com>
+
+       * loop.c (check_final_value): Check for biv use before checking for
+       giv use.  Check for both biv and giv uses.  Always set last_giv_use
+       if there is a giv use.
+
 2000-09-01  Richard Henderson  <rth@cygnus.com>
 
        * config/ia64/ia64.md (mulsi3): Use grfr_register_operand.

diff --git a/gcc/loop.c b/gcc/loop.c
index 5c70055..c5e5c4c 100644 (file)
--- a/gcc/loop.c
+++ b/gcc/loop.c
@@ -5677,19 +5677,25 @@ check_final_value (loop, v)
          if (GET_CODE (p) == INSN || GET_CODE (p) == JUMP_INSN
              || GET_CODE (p) == CALL_INSN)
            {
-             if (biv_increment_seen)
+             /* It is possible for the BIV increment to use the GIV if we
+                have a cycle.  Thus we must be sure to check each insn for
+                both BIV and GIV uses, and we must check for BIV uses
+                first.  */
+
+             if (! biv_increment_seen
+                 && reg_set_p (v->src_reg, PATTERN (p)))
+               biv_increment_seen = 1;
+               
+             if (reg_mentioned_p (v->dest_reg, PATTERN (p)))
                {
-                 if (reg_mentioned_p (v->dest_reg, PATTERN (p)))
+                 if (biv_increment_seen)
                    {
                      v->replaceable = 0;
                      v->not_replaceable = 1;
                      break;
                    }
+                 last_giv_use = p;
                }
-             else if (reg_set_p (v->src_reg, PATTERN (p)))
-               biv_increment_seen = 1;
-             else if (reg_mentioned_p (v->dest_reg, PATTERN (p)))
-               last_giv_use = p;
            }
        }